The target_starttimer, target_stoptimer and target_checkpoint entities

The targets above are used as they are called. A starttimer starts the timer; a stoptimer the opposite and a checkpoint is used in the middle of the run so the player can look if he improved his previous time between those triggers.
These timers can only be used in Defrag runs:

Map: cmc04_bliccer

If you want to build such timers then you have to do a copy first. Go into your Quake III Arena/defrag/scripts folder and copy the file called defrag.def into your Quake III Arena/baseq3/scripts directory. Start the editor and load the tutorialmap
(defragtutorial1.map). Now create a new trigger on the striated texture and convert it into a trigger_multiple (while you have selected the trigger open the entity menu by a right mouse button click -> trigger ->
trigger_multiple). After that deselect the brush (Esc) and put a target_starttimer in front of the trigger (entity menu -> target -> target_starttimer -> a red box should appear):

Deselect the entity and select, first the brush, then the target_starttimer and press Ctrl+k for connecting them. A red line should link the two entities now like in the screenshot above. If you want to have a checkpoint in your map just do the same as for
the start timer. Only create a target_checkpoint instead of a target_starttimer. Now guess what you have to do for a stop timer. Compile the map, start it in defrag and have fun in your first map with timers.

Here you can get the maps for this tutorial (place it into baseq3/maps):